A curious and unexpected change was here noted in the subject, Mr. Koffka, who, while concentrating his attention to the uttermost, began unawares to develop a new system of expressive movements of the head. When the distance between the sheets was relatively great, he had been in the habit of turning his head and eyes in the direction of the sheet intended, and as the distances became less he had reacted only by a turning of the eyes. But now, as the distances were still further decreased, he began again to react by means of head movements, and these were of exaggerated magnitude, for which he would compensate, as it were, by an eye-movement in the opposite direction. Although the head movements decreased in scope as the distances between the sheets were steadily decreased, they still were always decidedly greater than the eye movements, which I was now normally led to expect and which could be judged without much difficulty. This form of reaction was much more satisfactory as a cue, and therefore it came to pass that, whereas in the preceding series I had made only 60% correct inferences when the angle was 1 degree, I now found that--the angle remaining the same--80% of my inferences were correct. (My final judgment I continued to base, as before, upon the position, and not upon the movement, of head and eye). The number of correct inferences continued relatively high, even after the distance between the papers was decreased tenfold,--as will be seen from the following table: Angle: 1 deg. 30' 15' 9' 7' 6' 5' 3' 2' Distance between the centres of two neighboring papers: 131 65 33 20 15 13 11 6-1/2 4mm. Percentage of correct inferences: 80 79 78 81 84 80 77 68 68% Beginning with an angle of 1' (distance between the centers of two neighboring papers = 2 mm.), the subject was unable to focus, with sufficient steadiness of vision, upon one paper alone, and the movements, for that reason, ceased to manifest themselves. Comparing the results obtained in the case of this subject with those obtained from two others, whose reactions had remained normal, B. and Miss St., we find that with them there were only 53% correct inferences in both cases (based each upon 200 tests), when the angle was 5'. In my errors, too, I often shot wider of the mark. In another series of 200 tests, in which Miss St. "merely thought of the places", I had a percentage of 56% correct inferences, and my errors did not become any coarser. Miss St. believed this a case of true telepathy, but I had been guided in my judgments entirely by her unwittingly made movements--or rather the direction--of her eyes. The magnitude of these movements bore a constant relationship to the distance between papers as it was conceived by the subject.